M-channel cosine modulated filter banks with linear phase analysis and synthesis filters

In this paper, we present the theory and design of a new class of cosine modulated filter bank with linear phase sub-filters. In contrast to 2M channel structures, so far reported in the literature, the proposed filter bank has only M bands, and all the sub-filters are linear phase. The filter bank uses only one prototype filter for both analysis and synthesis side and structurally guarantees perfect reconstruction (PR) property. The modulation used is DCT II, which ensures fast and efficient implementation. Necessary and sufficient conditions for PR and linear phase are derived and design examples are presented.